The Assessment, Comorbidity and Health Services Research Core will support the intervention projects and pilot studies in the following areas: 1) recruitment and screening of patients eligible for participation in the studies; 2) retention of subjects participating in the studies; 3) assessment of subjects for the presence of comorbid conditions which might influence both compliance with and response to the interventions; 4) functional assessment of subjects participating in the intervention studies including use of self-report measures and performance-based measures of physical capacity; and 5) analysis of cost- effectiveness and cost-utility of the interventions. To accomplish these goals, the Core has the following specific aims: 1) To develop registries of patients with the diagnoses of intermittent claudication and congestive heart failure; 2) To develop and implement a comprehensive assessment protocol including demographic, clinical, psychosocial, and functional status measures for use in the IS, IDS, and all pilot studies; 3) To collect data on the consumption of health care resources, including both direct and indirect costs of treatment and total, out-of-pocket, and third-party costs of health services utilized, by subjects in all treatment arms of the IS, IDS, and pilot studies; 5) To collect data on quality of life outcomes associated with the different arms of the interventions; and 6) To conduct cost-effectiveness and cost- utility analyses of the interventions, using accepted methodology. The Assessment, Comorbidity and Health Services Research Core will also provide opportunities to enhance the development of research skills of junior investigators, including postdoctoral fellows and junior faculty, and research associates identified through the Research Development Core, including providing support for Pilot Research Projects on topics related to the activities of the OAIC. Thus, the Core will be an integral part of the University of Maryland OAIC through the construction of patient registries, collection of data on comorbidities and functional and health status, conduct of cost-effectiveness analyses, and education of investigators in the areas of clinical epidemiology and health services research.